1. Field of the Invention
The present invention relates to an electrolyte composition and an energy storage device including the same, and more particularly, to an electrolyte composition and an energy storage device including the same that can improve output and life characteristics.
2. Description of the Related Art
Among next generation energy storage devices, a device called an ultracapacitor or a supercapacitor has been highlighted as a next generation energy storage device due to high charging and discharging speed, high stability, and eco-friendly characteristics. Currently, as the representative supercapacitors, there are a lithium ion capacitor (LIC), an electric double layer capacitor (EDLC), a pseudocapacitor, a hybrid capacitor, etc.
An electrolyte composition of the LIC is prepared by dissolving a lithium salt such as LiPF6 in a carbonate non-aqueous solvent. For the effective dissolution of the lithium salt, a high permittivity solvent such as ethylene carbonate (EC) or propylene carbonate (PC) should be used. However, this cyclic carbonate solvent is solid or very viscous at room temperature. Therefore, generally, a mixed solvent of a cyclic carbonate solvent and a linear carbonate solvent having relatively low permittivity and low viscosity is used.